Any real difference between a 250- or 300-hp 327 in a Chevy sedan versus in the same year Corvette?.

[Bill Pressler]

...other than the Corvette will have the snazzier "Corvette" valve covers?

There is a moderator over on the Edmunds site that is absolutely unable to give Studebaker any credit where credit is due. He will correct anyone using the term "Avanti engine" with saying "There is no such thing as an Avanti engine...it's a Studebaker engine with certain special parts....anyone could make the conversion in an afternoon".

He concedes he is the son of a Packard employee and refers to Studebaker-Packard as "Packard-Studebaker". This to me speaks volumes.

He says Corvette engines are unique to Corvettes, and that would be even in the example used in my title.

I respectfully call "b*lls**t", but am able to admit I'm wrong.

If the Corvette engine really is different, to what end? They sure didn't get any more horsepower out of it than that same displacement/hp engine in a Biscayne 4-door.

I think the later "L" high-performance engines, which weren't available in any other Chevrolet, would probably be unique (specific block, etc.)

[Orestudeguy]

Hi Bill,
I have experience with this. The difference between the 250 horsepower 327 and the 300 horsepower 327 is a couple of things.
The 300 horse engine (in 1964) came with the 202 "big intake valve "fuelie" heads and the larger 2 1/2 inch rams horn exhaust mainifolds.
And the AFB carburator.
If memory serves me well, those three items wre the only difference.

[Gunslinger]

The engines destined for Corvettes may also have 4-bolt mains, though not all will. The block casting is usually the same and carries the same casting number, but the machining in certain areas is sometimes different.

The crankshafts may well be different...cast vs. forged in most Corvette engines of the era.

The water pump is different as well. There's long water pumps, short water pumps and Corvette water pumps. The Corvette water pump is a short water pump with a heavier bearing.

The differences between standard Chevy small blocks and Corvette blocks are not that many, but are important.

[Skip Lackie]

Admittedly, the Avanti engine could be ordered in any Lark in 63 and 64. But I don't think there's very much that's unique to the 62-64 Corvette engines either, except for some trim items and whatever was required to make it fit into the Corvette. Both the 250 and 300 hp versions of the 327 were available in both Corvettes and full-size Chevys. There are a number of differences between the two engines, the most obvious being the much larger Carter AFB on the 300 hp unit.

I still own a 62 Impala equipped with the 300 hp 327 that I bought new. The 300 hp 327 was a commonly ordered option in both Corvettes and big Chevies. It has the same compression ratio, 2.5-inch rams horn manifolds and dual exhausts as the Corvette. The parts book shows the same cylinder heads were used on both Vettes and big Chevies with the 300-327 in 62 and 63.

Clearly, some later years of Corvettes were available with Vette-unique engines, but I don't believe that was true while the Avanti was in production.

[Bill Pressler]

Honestly, I'm surprised that there's any difference besides valve covers/air cleaner, between a '64 Impala 327 with 250 or 300 hp, and a '64 Corvette with either of the same engines. If the Corvette was different, it seems like for naught, with no different horsepower ratings than what got put in the regular passenger cars. Thanks for the info.

The engines destined for Corvettes may also have 4-bolt mains, though not all will. The block casting is usually the same and carries the same casting number, but the machining in certain areas is sometimes different.

The crankshafts may well be different...cast vs. forged in most Corvette engines of the era.

The water pump is different as well. There's long water pumps, short water pumps and Corvette water pumps. The Corvette water pump is a short water pump with a heavier bearing.

The differences between standard Chevy small blocks and Corvette blocks are not that many, but are important.

[Orestudeguy]

The long snout water pump was first used in 1969 small block powered passenger cars. Same thing for the large journal crankshafts being used first in 1969.
Four bolt mains were first used in 1969 small blocks as well.
Oil pans on the Corvette were different as well, more capacity.

[Skip Lackie]

At the risk of beating a dead horse (again), I think it's important to compare what Stude was doing with Avanti engines in 1962 and 63 with what Chevy was doing with Corvette engines in 62 and 63. Comparing the uniqueness of 1963 Avanti engines with the uniqueness of 1970 Corvette engines doesn't seem very sensible -- who knows what Stude would have put into Avantis if they were still building them in 1970?

Anyway, I dug out a 1963 Chevy parts book and looked up a few critical engine parts for 1962 and 63. The following parts were common to both big Chevy and Corvette engines with the same horsepower rating: block, heads, cam, valves, and water pump. Two crankshafts were listed for 62-63 Corvettes, one of which was also used in high performance Chevys. The second one was unique to the Corvette, though it appears that that unique crank was only used in fuel-injected engines. The listing was a little confusing -- Chevy parts books are not as easy to use as Stude parts books.

Clearly, the FI engines were unique to Corvettes, but those aside, I couldn't find much else to differentiate Corvette engines from the high-performance engines that were available in big Chevies in 1962 and 63.

[Bill Pressler]

Thanks all for the info, and thanks, Skip, for digging out the Chevy manual!

[KGlowacky]

I would like to add, I worked (owned) a corvette restro shop for the past 25 years and there is differences in the complete engines BUT only in things like water pumps and oil pans. Now saying that Original Corvette engine used only certain casting numbers BUT these same casting numbers were used in other Chevy cars. There are some casting numbers NEVER used in a Corvette that were used in high performance engines. I have a rather rare 65 327 block in my garage that has a casting number that was only used in the Corvette during the 1965 Engine factory labor strike. This engine did not come from a Corvette but when the Corvette assembly line ran out of engines during the strike they went and got these from the regular car line. They had the high performance heads and other goodies on them but they are all the same in general. Corvette owners are nuts over numbers. A lot of owners think because certain casting numbers came in Corvettes they were exclusive to Corvettes. That is not true. There are a lot of Chev small block engines that NEVER came in Covettes so they could never be considered Corvette Engines, although they are the same in every spec. One more example, I also have a 1970 LS1 350/350hp block in my garage. It came out of a 70 Chevelle SS. The casting ends in 010. It is a 4 bolt main, steel crank and pink rods. If you look in the corvette #'s bible it will say 010 blocks came in LS1 1970 Corvettes. That is true but they also came in SS Chevs also. Sorry to ramble but these Corvette owners are full of alot of info not totally true.